US1338815A - Concrete vessel - Google Patents

Description

L. COKE-HILL.

CONCRETE VESSEL.

APPLICATION FILED SEPT. 19, 1918.

Patented May 4,1920. I

//7 l/enlvr Llonel Coke-Ill LIONEL COKE-HILL, or noNraEAL, QUEBEC, CANADA.

CONCRETE VESSEL.

Specification of Letters Patent.

Patented May 4., 1920.

Application filed. September 19, 1918. Serial No. 254,882.

To all whom it may concern:

Be it known that I, LIONEL COKE-HILL, a subject of the King of Great Britain, residing at the city of Montreal, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Improvements in Concrete Vessels, of which the following is a full, clear, and exact description.

This invention relates to improvements in concrete vessels and the object of the invention is to provide a construction in which the concrete is so disposed that its greatest inherent strength is utilized.

A further object is to provide a concrete vessel so constructed that the amount of metal reinforcement required will be very much less than that ordinarily used.

A still further object is to provide a concrete vessel so constructed that the interior molds are practically uniform throughout. Various other objects and advantages will be apparent from the following description.

It is well known that the strength of concrete when subjected to tension, flection or torsion stresses is very little, as compared with its strength when subjected to compression stresses. In a concrete vessel, as ordinarily contructed, the sides are substantially flat slabs between the frames and these fiat slabs are subjected by water pressure and wave actionto constantly varying flection stresses. In order to make the structure sufficiently strong, a very large amount of metal reinforcement is required, owing to the limitations of weight imposed by the nature of the structure. Apart from the difficult form work, this great amount of reinforcement makes an ordinarily constructed concrete vessel an extremely expensive proposition, as compared with a concrete factory or warehouse building of the same weight. A reduction in the amount of metal can be effected only by greatly increasing the amount of concrete and a point is soon reached where the increased dead weight of the hull encroaches so seriously on the cargo carrying capacity of the vessel that it becomes an unpractical structure. The tendency, therefore, is to use the thinnest possible concrete slab and supply the requisite strength with. reinforcement. This practice yields a comparatively flexible structure, so that the concrete is constantly subjected to considerable flection or panting stresses, which it is not well able to withstand, and the tendency to crack and disintegrate is very great. These comparatively thin slabs also require support at frequent intervals, so that the frames are spaced quite close together.

According to the present invention, the hull is constructed of a series of approximately semi-circular slabs or arches, the arches being disposed in the longitudinal direction of the vessel and extending from the sheer line through the keel to the opposite sheer line. This construction is such that the concrete is always in compression, and therefore its ability to' withstand external pressure is developed to the maximum. The edges or wings of the arches meet and form the usual frames within the vessel. Longi tudinal stiffening is imparted. by the keel and a suitable number of"ke'elsons and stringers. The addition of a concrete deck resting on posts extending to the keel or keelsons completes the hullproper. In order to reduce the resistance of the water to the vessels motion, a smooth outer sheathing is connected to the arches at their crowns. This sheathing is apertured in suitable places to admit water pressure to the convex surfaces of the arches forming the hull proper. It therefore follows that the outer sheathing has equal pressures on opposite sides thereof and has no water pressure to sustain except the wave action. This sheathing may be of any suitable material, either wood, metal or concrete. As the concrete of the hull proper is so disposed as to be constantly in compression, it is clear that a minimum amount of metal reinforcement will be required. Obviously, the usual amount of longitudinal reinforcement will be necessary. This reinforcement is provided by the outer smooth concrete walls or equivalent internal longitudinal walls which with the deck and bottom form a truss, in the usual manner, which is sufliciently stiff to resist hogging or sagging when the hull is subjected to wave action. If cracks should develop in the concrete of the arches, the fact that the concrete is in constant compression will cause the cracks to close up, whereas exactly the opposite condition prevails with a flat" slab in which the working causes the cracks to grow.

In the drawings which illustrate the in vention;-

Figure 1 is a vertical longitudinal section of a vessel constructed according to this invention.

Fig. 4 is a half cross section on the line 44, Fig. 2.

Fig. 5 is a view similar to Fig. 3 showing a slight modification.

Fig. 6 is a cross section in the forward part of the vessel.

Fig. 7 is a cross section on the line 7-7, Fi 3.

ig. 8 is a cross section on the'line 8-8,

Fig. 3.

eferring more particularly to the drawings, 11 designates a plurality of semi-circular walls or arches which form the hull of a vessel and which extend from sheer line to sheer line through the keel, the arches being disposed with their extremities fore and aft. The extremities of the arches meet and form internal projections or frames 12. Transverse bulkheads 13 may be provided where desired, preferably extending between the frames 12 and forming continuations thereof across the hull. The keel 14 and other longitudinal members 15, as well as the deck 16, give strength to the vessel in the longitudinal direction, the deck being supported by any suitable number of posts 17 as well as by the frames. The inner or concave surface of each arch may be struck from a center 18, while the outer or convex surface is struck from a center 19 nearer the center line of the vessel, with the result that the wall thickness of each arch increases from the crown toward the extremities, thus giving greater strength Where the arches unite. A smooth surfaced outer sheathing 20 is connected to the arches at their crowns, the outer surface of this sheathing being tangent to the convex surfaces of the arches. This outer sheathing or wall 20 may be of concrete or any other suitable material, and is provided. with apertures 21, which admit water into the spaces 22 formed between itself and the arches. This admission of the water to the spaces 22 equalizes the pressure on opposite sides of the plain wall, so that it has very little more than its own weight to support except the stresses to which it is subjected as forming part of the longitudinal stiffening. At the same time, this admission of water into the spaces 22 brings the actual water pressure on the hull against the convex surfaces of the arches forming the hull proper, which formation is better able to withstand the pressures than a flat wall, as is well known. Apertures 23 may be formed through the keel and longitudinal members in the spaces 22, these apertures being restricted either by their size or by means of valves, so as to regulate the flow of water in the spaces from side to side of the vessel as it heels. The apertures 21 through the wall 20 will also be sufficiently restricted to seriously retard the flow of water into or out of the spaces 22 as the vessel rolls, this restriction being due either to the size of the apertures or to the provision of valves.

In Fig. 5 a slight modification is shown which consists in terminating the corrugated portion of the hull a few feet below the water line and carrying a lower deck 24 clear to the external shell so that the full width between external sheathings is available for cargo and additional buoyancy. The frames in this portion which are subjected to comparatively slight pressures are constructed in the usual way.

The arches may be duplicated within the vessel so as to form complete circular tanks, as shown at 26, Fig. 2. Such a construction will not only form a vessel suitable for oil or grain cargoes, but will also form a vessel particularly well adapted to withstand internal pressures. If a vessel is particularly designed for oil or grain carrying or the like, the entire hull may be formed of these circular tanks, so that great strength will be obtained and the buoyancy of the vessel will be very little affected by rupture of the bottom in or between any of the tanks. Various modifications may be made in the structure, such as the provision of longitudinal bulkheads connecting the extremities of the arches or dividing the vessel into two or more compartments. It is preferred to increase the depth of the frames. 12 from deck to bilge and to further increase them from bilge to keel'with a still further in crease at the bilge to adequately stiffen the structure. This will be clearly seen in Figs. 6, 7 and 8. V

WVhen the vessel is launched,.water enters the spaces 22 through the apertures 21 and rises to the level, so that the pressure is equalized on opposite sides of the wall. 20 and. the real pressure sustained by the hull is exerted against the convex surfacesof the arches. Owing to the formation, this arch structure of the same thickness as a flat wall will withstand much greater pressures, as the concrete is entirely in compression. Obviously, a much thinner and lighter curved wall with much less metal reinforcement will. withstand the same pressure as a heavier flat wall with more metal reinforcement. It follows, therefore, that a vessel constructed according to this invention may be built, having the same strength as a concrete vessel constructed in the ordinary manner but with the use of much less metal reinforcement.

When the vessel rolls if the side spaces 22 are connected either through openings or valves in the longitudinal keelsons or by other suitable means, the water in these side spaces will act automatically as an antirolling device thus replacing the specially constructed tanks at present used. By the addition of valves to apertures 21 the side spaces 22 may be utilized for the reception of any liquid cargo desired when the valves are closed with exactly the same results as when sea water is admitted to these spaces.

The radii from which the arches are struck are preferably uniform throughout the vessel. Therefore, a single set of inside molds used over and over again will be all that is necessary to mold the entire inner surface of the vessel. In certain instances at bow and stern, special molds will be required for the spaces 22 but, for the most part, the outer surfaces of the arches may be made from the same mold. This will obviously reduce the cost of mold or form work to a minimum.

Having thus described my invention, what I claim is 1. A concrete vessel having the hull thereof corrugated, the corrugations extending transversely.

2. A structure according to claim 1, in which the corrugations are approximately semi-circular and all arranged with their convex surfaces outward.

3. A concrete vessel having the hull thereof formed of a plurality of arches the spans of which are disposed longitudinally, each arch extending from the sheer line on one side through the keel to the sheer line on the other side.

4. A device according to claim 3, in which the extremities of the arches unite to form internal frames for the hull.

5. A device according to claim 3, having longitudinal members spanning the arches and stiffening the structure longitudinally.

6. In combination with a device according to claim 3, an outer smooth sheathing connected to the arches at their crowns.

7. A device according to claim 6, in which apertures are formed through the outer sheathing below water level to admit water between the sheathing and arches.

8. In combination with a device according to claim 5, a smooth outer sheathing attached to the arches on their crowns having apertures below water line to admit water between sheathing and arches, said longitudinal members being apertured in the spaces between the arches and sheathing.

9. A device according to claim 8, in which the apertures of the sheathing and longitudinal members are sufiiciently restricted to delay water in the spaces between the sheathing and arches in equalizing and in 12. A device according to claim 3, in

which the convex surfaces of the arches are struck from centers nearer the longitudinal axis of the vessel than the concave surfaces whereby the arches increase in thickness t0- ward their extremities.

13. A device according to claim 6, in which the outer surface of the sheathing is approximately tangent to the convex surfaces of the arches, whereby the sheathing and arches merge.

14. A concrete vessel having an outer smooth sheathing and transverse corrugated hull proper, whereby spaces are formed at intervals extending from sheer line to sheer line through the keel.

15. A device according to claim 14 in which a deck is continued to the outer sheathing forming horizontal division walls in said spaces below water line, the corrugated structure terminating at said deck.

In witness whereof, I have hereunto set my hand.

LIONEL COKE-HILL.

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